Effect of pipes in heat pump system on electric vehicle energy saving

ABSTRACT

Refrigerant pressure drop and temperature change in pipes are normally ignored in the thermodynamic analysis of traditional vehicle air conditioning system, this will result in serious errors. In this Paper, pressure drop and temperature difference are simulated in different pipes of electric vehicle (EV) heat pump system to analysis the effects of pipes in the actual EV heat pump system. The results indicate that the greater the mass flow, the faster pressure drop increases, the temperature difference decreases. Pressure drop of saturated liquid refrigerant is smaller than that of saturated gas refrigerant at the same saturation pressure and mass flow rate. The higher the refrigerant pressure (no phase change), the slower pressure drop decreases, the faster the temperature difference decreases. Pressure drop decreases with the increment of bending angle of the pipe. For EV heat pump system, suitable valves and less branches are helpful for energy saving of the system. Shortening the pipe between compressor and condenser can reduce temperature change obviously. Pressure drop per unit length in the pipe between evaporator and compressor is large especially in heating mode because of lower refrigerant density. It even reaches to over 100 times of that in the pipe between condenser and throttle valve in heating mode and has negative effects on the performance of the system. If the evaporator is closer to the compressor and the number of branches is less, then pressure drop will decrease a lot, which will be advantageous for energy saving of the heat pump system.     

典型有机磷酸酯阻燃剂分析方法研究进展

有机磷酸酯(OPEs)是一类重要的有机磷阻燃剂,近些年逐渐取代了溴代阻燃剂,广泛应用于各行各业,也因此导致在多种环境介质中有较高的暴露量和潜在风险。已有研究表明,OPEs具有一定的毒理效应,对人体及其他生物均有潜在危害。本文综述了近年来国内外OPEs的检测技术,详述了不同环境介质OPEs的前处理方法。结果表明,目前固相萃取(SPE)和固相微萃取(SPME)仍是水样前处理的主要方法;对于固体样品,加速溶剂萃取/加压液相萃取(ASE/PLE)和微波辅助萃取(MAE)应用较多;虽然大气样品仍以固体吸附剂方式为主,但已向在线一体化方向发展;而生物样品的前处理方法多与水样和固体样品方法相似;但是对于复杂环境介质中OPEs样品的前处理较为困难,方法有待改善;气相色谱-质谱联用(GC-MS)和气相色谱-氮磷检测器(GC-NPD)对弱极性和易挥发的OPEs分析效果好,而强极性和难挥发的OPEs多用液相色谱-质谱联用(LCMS);气相色谱-质谱串联(GC-MS/MS)、液相色谱-质谱串联(LC-MS/MS)和高效液相色谱-质谱串联(UPLC-MS/MS)等对多种复杂的环境介质中的OPEs均有较好的检测分析效果,但并未普及。最后,对OPEs分析测试方法的发展趋势提出了展望。     

畜禽环境中抗生素的去除及其风险评估

抗生素作为饲料添加剂广泛应用于畜禽养殖业,造成养殖环境抗生素大量蓄积,尤其是在畜禽粪便中,长期的积累不仅污染养殖场内土壤环境,残留的抗生素还会随畜禽粪便进入周边水体及农田环境,威胁农作物及人体健康。目前,国内相关研究主要集中在抗生素的降解工艺及降解规律方面,而对其去除效率的影响因素及风险评价研究相对较少。笔者综述了国内外抗生素的降解转化及去除方式等的研究进展,并概述了抗生素在畜禽环境中的生态风险评估的研究现状,为抗生素的高效去除、风险预估及畜禽粪便资源化安全利用提供理论基础和技术支撑。     

Magnetotactic bacteria: Characteristics and environmental applications

• Magnetotactic bacteria (MTB) synthesize magnetic nanoparticle within magnetosomes. • The morphologic and phylogenetic diversity of MTB were summarized. • Isolation and mass cultivation of MTB deserve extensive research for applications. • MTB can remove heavy metals, radionuclides, and organic pollutants from wastewater. Magnetotactic bacteria (MTB) are a group of Gram-negative prokaryotes that respond to the geomagnetic field. This unique property is attributed to the intracellular magnetosomes, which contains membrane-bound nanocrystals of magnetic iron minerals. This review summarizes the most recent advances in MTB, magnetosomes, and their potential applications especially the environmental pollutant control or remediation. The morphologic and phylogenetic diversity of MTB were first introduced, followed by a critical review of isolation and cultivation methods. Past research has devoted to optimize the factors, such as oxygen, carbon source, nitrogen source, nutrient broth, iron source, and mineral elements for the growth of MTB. Besides the applications of MTB in modern biological and medical fields, little attention was made on the environmental applications of MTB for wastewater treatment, which has been summarized in this review. For example, applications of MTB as adsorbents have resulted in a novel magnetic separation technology for removal of heavy metals or organic pollutants in wastewater. In addition, we summarized the current advance on pathogen removal and detection of endocrine disruptor which can inspire new insights toward sustainable engineering and practices. Finally, the new perspectives and possible directions for future studies are recommended, such as isolation of MTB, genetic modification of MTB for mass production and new environmental applications. The ultimate objective of this review is to promote the applications of MTB and magnetosomes in the environmental fields.     

Diffusive gradients in thin films using molecularly imprinted polymer binding gels for in situ measurements of antibiotics in urban wastewaters

• Selective molecularly imprinted polymer (MIP) binding gel was prepared. • MIP-DGT showed excellent uptake performance for antibiotics. • In situ measurement of antibiotics in wastewaters via MIP-DGT was developed. • The MIP-DGT method was robust, reliable, and highly sensitive. Urban wastewater is one of main sources for the introduction of antibiotics into the environment. Monitoring the concentrations of antibiotics in wastewater is necessary for estimating the amount of antibiotics discharged into the environment through urban wastewater treatment systems. In this study, we report a novel diffusive gradient in thin films (DGT) method based on molecularly imprinted polymers (MIPs) for in situ measurement of two typical antibiotics, fluoroquinolones (FQs) and sulfonamides (SAs) in urban wastewater. MIPs show specific adsorption toward their templates and their structural analogs, resulting in the selective uptake of the two target antibiotics during MIP-DGT deployment. The uptake performance of the MIP-DGTs was evaluated in the laboratory and was relatively independent of solution pH (4.0–9.0), ionic strength (1–750 mmol/L), and dissolved organic matter (DOM, 0–20 mg/L). MIP-DGT samplers were tested in the effluent of an urban wastewater treatment plant for field trials, where three SA (sulfamethoxazole, sulfapyridine, and trimethoprim) and one FQ (ofloxacin) antibiotics were detected, with concentrations ranging from 25.50 to 117.58 ng/L, which are consistent with the results measured by grab sampling. The total removal efficiency of the antibiotics was 80.1% by the treatment plant. This study demonstrates that MIP-DGT is an effective tool for in situ monitoring of trace antibiotics in complex urban wastewaters.     

Assessing the land use type and environment factors affecting groundwater nitrogen in an arid oasis in northwestern China

Environmental Science and Pollution Research - Identifying the magnitude and seasonal variability of groundwater nitrogen (N) under various land use types and quantifying the contribution of their...     

长江经济带城镇化与生态环境耦合协调效应测度与交互胁迫关系验证

基于长江经济带9省2市2000～2017年数据,建立长江经济带城镇化与生态环境交互耦合协调发展评价体系,运用耦合协调模型和交互胁迫模型,探究二者的动态关系。结果表明:在时间序列上,2000～2017年,长江经济带的城镇化与生态环境之间的协调性呈现稳步上升态势,整体处于良好耦合协调阶段。研究期初,生态环境综合指数高于城镇化综合指数;研究期末,城镇化综合指数高于生态环境综合指数。在空间格局上,二者的协调发展态势存在由东部区域沿中西部区域下降的空间差异特征。长江经济带的城镇化与生态环境之间存在交互胁迫关系,演变状态符合双指数函数特征。长江经济带区域内各省市存在城镇化与生态环境动态耦合关系的空间分布不均衡,经济较发达地区城镇化水平较高,经济欠发达地区生态环境受恶化风险较大。     

异戊醇低压热解的同步辐射真空紫外光电离质谱研究

作为新兴生物燃料,大分子醇类燃料在低压下的火灾安全基础迫切需要得到深入研究。热解过程作为火灾过程的初始阶段直接控制着火过程,火灾中碳烟颗粒的产生也依赖于热解反应,因此可燃物的低压热解研究在其低压火灾基础研究中具有重要意义。利用同步辐射真空紫外光电离质谱方法研究了异戊醇在0.2atm下的流动反应器热解,探测到了20余种热解产物,包括烯丙基自由基和C_4H_8O、C_5H_8、C_6H_6等同分异构体,并测量了其摩尔分数。基于实验结果,对燃料分解路径和主要产物的生成及消耗路径进行了探讨。与本组之前正戊醇热解实验的对比表明,由于存在支链结构,异戊醇在热解中比正戊醇更容易产生戊烯、丁烯和丙烯,但更少地产生乙烯。此外,异戊醇在热解中能够生成更多的丙炔和丙二烯等环状化合物前驱体,令其苯和1,3-环戊二烯的生成量更高,表明异戊醇比正戊醇更易于生成多环芳烃和碳烟。     

行为经济学视角下矿工不安全行为仿真分析

为了分析影响矿工不安全行为决策的成本收益因素,扩展不安全行为的研究方向,基于行为经济学,构建矿工不安全行为决策模型,模型包括矿工属性、管理者属性以及矿工之间的交互影响规则。利用Netlogo工具进行仿真模拟,探讨不同影响因素对不安全行为产生的影响程度。结果表明:正向激励水平对抑制不安全行为效果显著,同时,维持合理的工作时间对保障安全生产意义重大,从而为煤矿企业控制不安全行为提供思路。     

Annual Nutritional Organ Mass Cycle of <Emphasis Type="Italic">Bufo gargarizans</Emphasis> (Cantor, 1842) in Response to Extreme High Temperature

The annual relative mass of storage organs cycle of Bufo gargarizans in southwestern China was studied from December 2005 to November 2006. We described how those organs changed in response to extreme temperatures. Energy reservation dropped to the lowest levels after dormancy for both sexes, and then increased for period of 4.25 month. However, the mass of these organs dropped again rapidly until August (liver) and September (fat bodies) due to the constraint from extreme high temperature occurred during the summer, and then non-significantly increased before hibernation. For ovaries, varied with a different profile to those of liver and fat bodies have a resting period of four months. In addition, the toads’ ovaries kept growing when the mass of liver and fat bodies declining accordingly during hibernation. Therefore, ovarian mass increased during the hibernation and non-hibernation period.